240: What could cause a clutch like symptom

[xactorocker]

Hey, this is going to be about my 85 245 with the m46 transmission.
so I want to start from the beginning of this problem. I started noticing when I would go over 30-35 in 3rd or high second gear with the gas all the way down like when trying to accelerate quickly or sometimes barely down at all. The car would start to stop accelerating and the engine would just keep revving up higher without the vehicle speed increasing. I know this sounds like the clutch is slipping but the clutch is only a few months old. I am just wondering if this could be being caused by anything like anything else, or must it be the clutch because its relatively new and should not be slipping already. And I hope one of you that knows more than me may have an answer. Thank you.

I attached a sound clip of the best I could capture the problem happening.
it happens 10 seconds in. http://bit.ly/2ZeAM3N

[apachechef]

Clutches can cause clutch like symptoms when they are oily.

[xactorocker]

[QUOTE=apachechef;5959517]Clutches can cause clutch like symptoms when

is there any way to burn it off without taking the trans out. also is there anyway this could be the clutch cable doing this? thank you.

[TestPoint]

It's not going to burn off if it is oily enough to slip. Tried that.

Cable too tight? Where on the pedal travel does the clutch disconnect.

[smoothdurban]

I have had my clutch cable slightly seize on me where it would slip under load because it wasn't allowing the clutch to return to the full engaged position.
It seemed to occur in 3rd and 4th gears.

If it was me I would start there, cheap and easy to check. Heck if you were local I would give you my old clutch cable after my hydro swap.

[TestPoint]

Originally Posted by smoothdurban

I have had my clutch cable slightly seize on me where it would slip under load because it wasn't allowing the clutch to return to the full engaged position.

Sure it wasn't the above. That is a very good thought I hadn't experienced or thought of.

[2manyturbos]

Originally Posted by xactorocker

Hey, this is going to be about my 85 245 with the m46 transmission.
so I want to start from the beginning of this problem. I started noticing when I would go over 30-35 in 3rd or high second gear with the gas all the way down like when trying to accelerate quickly or sometimes barely down at all. The car would start to stop accelerating and the engine would just keep revving up higher without the vehicle speed increasing. I know this sounds like the clutch is slipping but the clutch is only a few months old. I am just wondering if this could be being caused by anything like anything else, or must it be the clutch because its relatively new and should not be slipping already. And I hope one of you that knows more than me may have an answer. Thank you.

I attached a sound clip of the best I could capture the problem happening.
it happens 10 seconds in. http://bit.ly/2ZeAM3N

I can't view your video, not that it matters. You may have a slipping cone clutch in the overdrive unit. That will behave just like a slipping clutch.

[xactorocker]

Originally Posted by 2manyturbos

I can't view your video, not that it matters. You may have a slipping cone clutch in the overdrive unit. That will behave just like a slipping clutch.

Hey I'm not really sure what a cone clutch is and I can't really find anything about it on the internet. Also how can I test it. And even more important if that is the problem where can I find it.

[hiperfauto]

Originally Posted by 2manyturbos

I can't view your video, not that it matters. You may have a slipping cone clutch in the overdrive unit. That will behave just like a slipping clutch.

The cone clutch isn't capable of handling the full torque of the engine so a one way clutch is used to augment the cone clutch. The design is fairly robust but doesn't tolerate dirt and debris very well.

Originally Posted by xactorocker

Hey I'm not really sure what a cone clutch is and I can't really find anything about it on the internet. Also how can I test it. And even more important if that is the problem where can I find it.

The cone clutch is part of the overdrive. It actually has 2 clutch surfaces. The inner clutch is for direct drive and reverse. Because of the aforementioned one way clutch, it's primarily for reverse. The outer clutch is for overdrive.

Replacements can be found here.

https://www.cvi-automotive.se/en/art...380689-st-also

The one way clutch is the more likely suspect. This is an updated version. Yours may look a little different.

https://www.cvi-automotive.se/en/art...-some-pj-types

[2manyturbos]

Originally Posted by hiperfauto

The cone clutch isn't capable of handling the full torque of the engine so a one way clutch is used to augment the cone clutch. The design is fairly robust but doesn't tolerate dirt and debris very well.



The cone clutch is part of the overdrive. It actually has 2 clutch surfaces. The inner clutch is for direct drive and reverse. Because of the aforementioned one way clutch, it's primarily for reverse. The outer clutch is for overdrive.

Replacements can be found here.

https://www.cvi-automotive.se/en/art...380689-st-also

The one way clutch is the more likely suspect. This is an updated version. Yours may look a little different.

https://www.cvi-automotive.se/en/art...-some-pj-types

Thanks for clarifying. It's been 30+ years since I have rebuilt and overdrive unit. All I really remember about them is they can develop slip in both directions to the point the car will barely move.

[xactorocker]

Hey, I adjusted the clutch cable. it looks like it was way off the arm was able to pull so much more than the 3mm it was supposed to. I still need to drive around and see if it fixed it but then you all for the help. if it happens again ill be back .

[xactorocker]

so yeah I adjusted the cable. it drove great for 2 days and today started to do the slipping like thing again. going to check if it stretched. you think I should try and do the clutch cable first before pulling the whole trans out again. thanks

[TestPoint]

Duh . . . .

How much can a cable cost?

[VB242]

A stretched clutch cable won't make the clutch slip, that happens when the cable is too tight. It could be hanging up though like the above post mentioned, you could disconnect both ends and see how easily it moves.

[smoothdurban]

Originally Posted by TestPoint

Sure it wasn't the above. That is a very good thought I hadn't experienced or thought of.

When I thought of it I told my indy to check that first before pulling the gearbox. He didn't listen and pulled the whole transmission out.
Needless to say I do all of my own work now.

Originally Posted by VB242

A stretched clutch cable won't make the clutch slip, that happens when the cable is too tight. It could be hanging up though like the above post mentioned, you could disconnect both ends and see how easily it moves.

Excellent idea.

[xactorocker]

ok thank y'all for the help. I ordered a cable for like 30 bucks. I'm just going to try and drive on slow roads till I can install it. also if anyone has any ideas about why my temp gauge would go up and up while accelerating in second would be much appreciated, Thank you

[xactorocker]

just wanted to let y'all know I replaced the cable and everything seems to now going good. will let you know if the problem comes back. thank you for the help.

[smoothdurban]

Originally Posted by xactorocker

just wanted to let y'all know I replaced the cable and everything seems to now going good. will let you know if the problem comes back. thank you for the help.

Did the old one have any signs of stiffness when you tried to operate it out of the vehicle?

[xactorocker]

no not really but I could have accidentally fixed the problem while yanking it out. but also it may have been stretching because I would adjust the clutch Fork to the 3mm its supposed to be. but when the problem happened again it would be more. and now with a new cable it seems better but I will keep this thread updated if it comes back.